Previously all sending through smtp appeared with the real user (user1, user2... ). Now all the sending through smtp (tcp 25) appear with the user "cpanel". This is correct? It affects to the bandwidth measurements of each user?

Code:

Top Email Relayers
Below are list of users who have relayed mail. They are listed in the order by
number of messages sent. You can click on the user/domain to view who
they sent the messages to.
User Domain Messages Sent Total Bytes Sent
cpanel 84 96448516
conxxx conxxxx.com 7 11157
freshxxx freshxxxx.com 7 16954
elaxxx ela.xxx 5 3773
root 5 50689
fiduxxxxc fiduxxxx.com 3 8063
.
.
.
.

These 84 (more less) emails are greater to megabayte and are of a single user "elaxxx" but they are seen like sended by cpanel and not like sended by "elaxxx".

The other 5 messages of "elaxxx" are through webmail (phpsuexec).

This is correct? It affects to the bandwidth measurements of each user?

I have the impression that bandwidth used by mail is not being measured correctly.